45 research outputs found
Monotropastrum humile var. humile is associated with diverse ectomycorrhizal Russulaceae fungi in Japanese forests
The original publication is available at www.springerlink.comArticleECOLOGICAL RESEARCH. 23(6):983-993(2008)journal articl
On the origin of mafic magmatic enclaves (MMEs) in syn-collisional granitoids: evidence from the Baojishan pluton in the North Qilian Orogen, China
1,2-Bis(diphenylarsino)ethane
The title compound, Ph2AsCH2CH2AsPh2 or C26H24As2, contains discrete molecules located on an inversion centre. Changes in the C-As-C angle upon coordination are noted
Metasomatic reaction bands at the Mt. Hochwart gneiss-peridotite contact (Ulten Zone, Italy): insights into fluid-rock interaction in subduction zones
Permo-Triassic unconformity- related Au-Pd mineralisation, south Devon, UK : new insights and the European perspective
An integrated mineralogical-geochemical study of unconformity-related Au-Pd occurrences within and around the Permo–Triassic basins of southwest England, UK, has confirmed the importance of low temperature (86±13°C), hydrothermal carbonate veins as hosts for the mineralisation. Fluid inclusion data for the carbonate gangue, supported by stable isotope (13C and 18O) and radiogenic (87Sr/86Sr) data, have identified three principal fluids: (1) a reducing calcic brine [>25 wt% salinity, 2)] originating in the sub-unconformity basement and an expression of advanced mineral–fluid interaction; (2) an oxidising sodic brine [~16 wt% salinity, >0.9 NaCl/(NaCl+CaCl2)] originating in the post-unconformity red beds under evaporitic conditions, and (3) an oxygenated, low salinity groundwater (<3 wt% salinity).="" the="" sodic="" brine="" is="" reasoned="" to="" be="" the="" parent="" metalliferous="" fluid="" and="" to="" have="" acquired="" its="" enrichment="" in="" au="" and="" pd="" by="" the="" leaching="" of="" immature="" sediments="" and="" intra-rift="" volcanic="" rocks="" within="" the="" local="" permo–triassic="" basins.="" metal="" precipitation="" is="" linked="" to="" the="" destabilisation="" of="" au="" and="" pd="" chloride="" complexes="" by="" either="" mixing="" with="" calcic="" brines,="" dilution="" by="" groundwaters="" or="" interaction="" with="" reduced="" lithologies.="" this="" explains="" the="" diversity="" of="" mineralised="" settings="" below="" and="" above="" the="" unconformity="" and="" their="" affinity="" with="" red="" bed="" brines.="" the="" paucity="" of="" sulphide="" minerals,="" the="" development="" of="" selenides="" (as="" ore="" minerals="" and="" as="" mineral="" inclusion="" in="" gold="" grains),="" the="" presence="" of="" rhodochrosite="" and="" manganoan="" calcites="" (up="" to="" 2.5 wt%="" mn="" in="" calcite)="" and="" the="" co-precipitation="" of="" hematite="" and="" manganese="" oxides="" are="" consistent="" with="" the="" overall="" high="" oxidation="" state="" of="" the="" ore="" fluids.="" a="" genetic="" model="" is="" proposed="" linking="" permo–triassic="" red="" beds,="" the="" mixing="" of="" oxidising="" and="" reducing="" brines,="" and="" the="" development="" of="" unconformity-related="" precious="" metal="" mineralisation.="" comparison="" with="" other="" european="" permo–triassic="" basins="" reveals="" striking="" similarities="" in="" geological="" setting,="" mineralogy="" and="" geochemistry="" with="" au,="" au-pd="" and="" selenide="" occurrences="" in="" germany="" (tilkerode,="" korbach-goldhausen),="" poland="" (lubin)="" and="" the="" czech="" republic="" (svoboda="" nad="" úpou="" and="" stupná).="" though="" the="" known="" au-pd="" occurrences="" are="" sub-economic,="" several="" predictive="" criteria="" are="" proposed="" for="" further=""
Molecular counting by photobleaching in protein complexes with many subunits: best practices and application to the cellulose synthesis complex
Igneous garnet and amphibole fractionation in the roots of island arcs: experimental constraints on andesitic liquids
To evaluate the role of garnet and amphibole fractionation at conditions relevant for the crystallization of magmas in the roots of island arcs, a series of experiments were performed on a synthetic andesite at conditions ranging from 0.8 to 1.2 GPa, 800-1,000 degrees C and variable H2O contents. At water undersaturated conditions and fO(2) established around QFM, garnet has a wide stability field. At 1.2 GPa garnet ? amphibole are the high-temperature liquidus phases followed by plagioclase at lower temperature. Clinopyroxene reaches its maximal stability at H2O-contents <= 9 wt% at 950 degrees C and is replaced by amphibole at lower temperature. The slopes of the plagioclase-in boundaries are moderately negative in T-XH2O space. At 0.8 GPa, garnet is stable at magmatic H2O contents exceeding 8 wt% and is replaced by spinel at decreasing dissolved H2O. The liquids formed by crystallization evolve through continuous silica increase from andesite to dacite and rhyolite for the 1.2 GPa series, but show substantial enrichment in FeO/MgO for the 0.8 GPa series related to the contrasting roles of garnet and amphibole in fractionating Fe-Mg in derivative liquids. Our experiments indicate that the stability of igneous garnet increases with increasing dissolved H2O in silicate liquids and is thus likely to affect trace element compositions of H2O-rich derivative arc volcanic rocks by fractionation. Garnet-controlled trace element ratios cannot be used as a prox